lb_tsn has PTP but it's not compatible with every 1588 profile. It is 802.1AS which I guess is a particular profile of 1588? Or something to that effect. It uses raw ethernet frames, not UDP like you (or your customer) might be expecting. So it will work with specific NICs (e.g. Intel I210 with the OpenAvnu gPTP code and Macs with thunderbolt ports).

If you need to use UDP you might need to modify the underlying PTP code to work with xtcp or another udp interface (e.g. if you need lighter weight) rather than using raw ethernet frames like lib_tsn. You will probably want to still make use of the timestamping feature of the real time mac I suppose. Perhaps you could port linux ptp to work?? That might not be too hard to get working with xtcp.